> "In real life groups CAN be argued to have certain characteristics to recognize members from non-members, hypocritical members, non-practicing members, posers

> "In real life groups CAN be argued to have certain characteristics to recognize members from non-members, hypocritical members, non-practicing members, posers and "fakes". So the "no true scotchman" fallacy breaks down when you're dealing with such nuances." On the other hand, where this most frequently pops up^, there is frequently no authoritative definition of what constitutes membership. Where there is, there is frequently no authoritative interpretation of the definition. ^ Any internet argument involving religion. The best you can typically manage is membership of particular sects which happen to have an agreed upon defining body. If the Pope says that you are not a Roman Catholic, you are pretty much by definition not a Roman Catholic. However if I define "Christian" in clear unambiguous terms, then point to my definition when asserting that somebody who claims to be a Christians is not a true Christian, then really I have said little of interest. That person may very well be a Christian by a definition other than my own (for instance, according to their definition), and I have justification for asserting that my definition is the true definition and theirs is false. The issue here is not quite that there is a true Scotsman fallacy going on. Rather it is a failure to agree to the definition of terms before engaging in the discussion.